The S-ICD System™ from Cameron Health, Inc., and Boston Scientific Corporation presents a new opportunity in cardiac rhythm management to reduce the complications associated with transvenous defibrillator systems. The defibrillator system itself may be implanted subcutaneously without accessing the vasculature or touching the heart.
An illustration is provided in FIG. 1. The system is implanted in a patient 10 with a canister 12 in the left axilla at about the level of the cardiac apex. A lead 14 is placed subcutaneously, beneath the skin and over the ribcage of the patient, with a first portion extending along the inframammary crease to the xiphoid, and then superiorly parallel to and about 1-2 cm to the left of the sternum. A proximal sense electrode 16, shocking coil electrode 18, and distal tip sense electrode 20 are provided along the parasternal portion of the lead 14. The entire system is implanted outside of the ribcage.
The canister 12 may further include such components as would be appropriate for communication (such as RF communication, inductive telemetry or other suitable communication linkage) with an external device such as a programmer 22. For example, during an implantation procedure, once the canister 12 and lead 14 are placed, the programmer 22 may be used to activate the canister 12 and/or direct/observe diagnostic or operational tests. After implantation, the programmer 22 may be used to non-invasively determine the status and history of the implanted device. The programmer 22 in combination with the canister 12 may also allow annunciation of statistics, errors, history and potential problems to the user/medical practitioner, and may also allow for updating of programming in the canister 12.
As shown in FIG. 2, a typical implant for the S-ICD System uses three incisions 30, 32, 34, and a sterile field represented by shape 36 is used to avoid the introduction of microorganisms that can cause infection. Some physicians have also used a two-incision approach by foregoing the superior sternal incision 34.
The subcutaneous-only placement prevents some of the more dangerous complications associated with infection, in particular, endocarditis which can result when an infection travels down a transvenous lead into the heart. However, infections, both systemic and superficial have been reported. In addition, some reports have shown that air pockets at either of incisions 32 or 34 can lead to inappropriate shocks within the first few weeks of implantation.
Alternatives and additional options are desired to reduce the number of incisions.